golang sqlx err missing destination name id in *main.User

In the process of learning to use golang operation of the database, the database query the database using sqlx encountered error message

Source as follows:

package main

import (
	"database/sql"
	"fmt"

	_ "github.com/go-sql-driver/mysql"
	"github.com/jmoiron/sqlx"
)

var DB *sqlx.DB

func initDb() error {
	var err error
	dsn := "root:123456@tcp(127.0.0.1:3306)/golang"
	DB, err = sqlx.Open("mysql", dsn)
	if err != nil {
		return err
	}
	DB.SetMaxOpenConns(100)
	DB.SetMaxIdleConns(16)
	return nil
}

type User struct {
	Id   int64          `db:id`
	Name sql.NullString `db:name`
	Age  int            `db:age`
}

func testSqlxQuery() {
	sqlstr := "select id,name,age from user where id=?"
	var user User

	err := DB.Get(&user, sqlstr, 3)
	if err != nil {
		fmt.Printf("select failed, err:%v\n", err)
		return
	}

	fmt.Printf("user:%#v\n", user)
}

func main() {
	err := initDb()
	if err != nil {
		fmt.Printf("init db failed, err:%v\n", err)
		return
	}
	testSqlxQuery()
}

After go build, execute error:

missing destination name id in *main.User

Using sql database query the database no problem, but the use of sqlx error, by comparison found that the object is a definition of the structure, tag tag does not lead to double quotes, quotes after the problem is solved.

type User struct {
	Id   int64          `db:"id"`
	Name sql.NullString `db:"name"`
	Age  int            `db:"age"`
}

For such problems should pay special attention in the use of tag use Remember increase in double quotes, to avoid such low-level errors.